If the new season of Girls makes you feel like a peeping Tom, try sitting through Stranger by the Lake, by veteran French writer-director Alain Guiraudie, without blushing at its graphic scenes of sex and nudity. Entirely confined to a lakeside cruising spot in the south of France, the movie is a virtuoso example of making the familiar feel treacherous and strange. What starts as a gay idyll—naked men lying languidly around a sparkling lake under a hot summer sun—quickly turns dark and claustrophobic when Franck (Pierre Deladonchamps) witnesses mustachioed hottie Michel (Christophe Paou) drowning his trick late one evening. When a police inspector invades this private world, Franck not only stays quiet about what he has seen, he embarks on a sexual relationship with Michel, unwilling to cool his infatuation. The audience may feel similarly—and that’s the point.

“He’s caught in between his desire on one hand and the major moral issues that are involved,” says Guiraudie, who reread Jean Genet’s 1947 novel of lust and murder, Querelle de Brest, while making Stranger. “I sort of identify with Franck, in a way, to see how far this kind of passion can lead you.”

It’s not just passion that keeps Franck in thrall to Michel. “It’s about loneliness and what you’re capable of when you’re in love,” says Deladonchamps. “He’s looking for something to fill up his life because he feels lonely and useless.” A second, platonic relationship between Franck and Henri, an overweight, middle-aged loner who sits away from everyone else, provides a tender and touching counterpart to Franck’s pursuit of Michel.

As for Michel’s lack of remorse and narcissism, Guiraudie says simply, “It’s an attitude that’s very current. You get together with someone and get what you can out of them and then you just toss them when you’re done.”

But while the murder remains the central, and most unsettling, image of the movie, Guiraudie is primarily concerned with the structure and etiquette that informs its sequestered community. As the camera zooms in on various couplings among the trees, we might be watching a nature doc, in which the perceptive, softly spoken police inspector who stumbles into this enclosed world is a stand-in for Sir David Attenborough, observing the mating rituals of a rare and curious species.

“I wanted to really show the joyful aspects of this world, the paradisiacal aspect of it,” says Guiraudie, who had to use stunt doubles for the movie’s most intimate scenes. “I wanted to show that this type of cruising does have its positive aspect. Most often when we see it in films it’s not portrayed that way at all—it’s closed and it’s repressed and it’s put aside.”

There’s also something sweetly old-fashioned about watching men on the prowl, unencumbered by cell phones and hook-up apps. “It’s something that’s very immediate and face-to-face, and that’s very democratic,” says Guiraudie. “It doesn’t matter if you’re rich or poor, fat or thin, handsome or ugly—everyone has their place. It’s very much like the world of the 1970s, where the idea of a separate gay culture and gay life seemed very promising. I think in other environments, on the Internet or bars or clubs, there’s much more compartmentalization. Maybe that’s why these cruising locations still exist, in spite of everything.”